4% of 9/11 workers developed asthma: study

August 28, 2007—About 4% of workers who dug through the World Trade Center site have since developed asthma, a new study shows.

That's 12 times the normal rate of adult onset asthma.

Worst hit were the rescue workers who arrived on Sept. 11 and Sept. 12, 2001, when the dust was thickest, sickening those who stayed longest, and those who did not wear masks.

"The dust from the World Trade Center collapse appears to have had significant respiratory health effects at least for people who worked at the site," said Thomas Frieden, New York City's health commissioner.

Previous studies have found up to 70% of 9/11 workers reported some kind of respiratory problem.

The new findings were released yesterday by the city Health Department and published in the journal Environmental Health Perspectives.

The large-scale survey of the more than 25,000 rescue and recovery workers enrolled in Mount Sinai Medical Center's 9/11 registry found that 926, or 3.6%, had developed asthma since 2001.

"We estimated an expected count of 77 cases," said the study authors, led by Katherine Wheeler of the city Health Department.

The rate jumped to 7% for those who arrived on the scene earliest, stayed longest and didn't wear masks.